Electron gun alignment device



y 0 F. G. 0555 3,510,926

ELECTRON 'GUN ALIGNMENT DEVICE Filed Jan. 2, 1968 2 SheetsSheet lRenae/6K & 0555,

Away/a4 Arraeva I May 12, 1970 F. G. OESS ELECTRON GUN ALIGNMENT DEVICE2 Sheets-Sheet 2 Filed Jan. 2, 1968 United States Patent US. Cl. 29-2519Claims ABSTRACT OF THE DISCLOSURE An aligning jig and method ofoperation to precisely align the G1 and G2 electrode apertures of anelectron gun is disclosed. An aligning mandrel is positioned in oneaperture and adjacent the other and rotated to view misalignment. Thesupporting cylinder is then manually distorted to produce aperturealignment.

The invention relates to a method of aligning electrodes forming part ofan electron gun and a device for accomplishing said alignment.

Structurally a typical electron gun comprises an annular cylinder havinga cathode at one end thereof, a G1 electrode mounted forwardly of thecathode and a G2 electrode positioned forwardly in the G1 electrode.Both the G1 and G2 electrodes are provided with central aperturesaligned with the electron emitting face of the cathode, the aperturesproviding openings to permit passage of the created electron beam. Theoperating efiiciency of any electron gun is importantly affected by theproper alignment of the G1 andG2 apertures. The more precise thisalignment the better the operating characteristics of the gun.

The present invention provides a method of obtaining precise alignmentof the apertures of the G1 and G2 electrodes. Though applicable toelectron guns of various configurations, the disclosed method isparticularly adapted to provide precise alignment for that type ofelectron gun structure as shown in my co-pending application filed oninstant date herewith and entitled Electron Gun Electrode MountingArarngement and Method of Fabrication.

Accordingly, it is the primary object of the present invention toprovide a method of obtaining precise alignment of the apertures of theG1 and G2 electrodes in a typical electron gun, and at a point in theassembly operation after mounting of the G1 and G2 electrodes to asupporting cylinder.

It is the further object of the invention to provide a method ofdetermining, if desired, the degree of misalignment existent in a givenelectron gun structure between the beam passing apertures of the G1 andG2 electrodes.

It is yet another object of the invention to provide a novel aligningjig not only adapted to determining the degree of misalignment betweenG1 and G2 apertures but providing an operative mode to realign, with ahigh degree of preciseness, misaligned G1 and G2 apertures in apartially fabricated electron gun.

These and other objects and features of the invention will becomeapparent in the course of the following description and from theexamination of the related drawings, wherein:

FIG. 1 is a fragmentary illustration of a coining operation adapted toprovide precise sizing of the beam passing aperture in a G2 electrode;

FIG. 2 is a central vertical sectional view, partially fragmentary, of ajig arrangement adapted to perform the method herein disclosed;

FIG. 3 is a visual representation of the device appearance to anoperator of an electron gun having misaligned G1 and G2 apertures;

3,510,926 Patented May 12, 197C ice FIG. 4 is a graphic representationof the device appearance to the operator of an electron gun havingaligned G1 and G2 apertures; and

FIG. 5 is a fragmentary sectional view taken along line 5-5 of FIG. 2illustrating the structure of FIG. 2 used to provide aperture alignmentfor electron guns wherein the apertures were misaligned upon originalfabrication.

Describing the invention in detail in directing attention initially toFIG. 2, an aligning jig indicated generally at 10 is provided having abase 12 with an upstanding support mandrel 14. The support mandrel 14 istelescopically received in the cylinder 16, as shown at the lowerportion of FIG. 2. The electron gun support cylinder 16 With the G1electrode 18 and the G2 electrode 20 assembled thereto is positionedover the supporting mandrel 14 so that the cavity of the G2 electrode 20telescopically receives the supporting mandrel 14. A clearance ofapproximately one to two-thousdanths of an inch may be provided betweenan external surface of the supporting mandrel 14 and the internalsurface of the cavity of the G2 electrode 20. An adjustment sleeve 22 ispositioned to surround the supporting cylinder 16 to provide backupreinforcement to the cylinder 16 and to bring the adjusting screws 24,24 into alignment with dimples 26, 26 formed in the peripheral wall ofthe cylinder 16. As noted in the referenced patent application thedimples 26 provide points of weld connection between the cylinder wall16 and the surface of the G2 electrode 20.

The support mandrel 14 is centrally apertured as at 28, said aperturehaving an alignment bearing 30 at its lower aspect. Aligning mandrel 32is carried in the cavity 2-8 and supported by the bearing 30 for precisealignment within base 12. The upper tip of the mandrel 32 is receivedwithin the G2 aperture 34 so that the axial edge of the mandrel 32 ispositioned immediately below the G1 aperture 36.

It will be understood that precise sizing of the G2 aperture 34 is animportant facet in obtaining the proper alignment of the apertures 36and 34 as hereinafter Will be described. Accordingly, and as apreliminary step prior to the utilization of the aligning device '10,the G2 electrode 20 is positioned in a sizing die indicated generally at40 in FIG. 1, said die comprising a base member 42 and a sizing member44 and sizing pin 46. The sizing pin 46 is provided with a diameteridentical with the alignment mandrel 32. The dotted line 48 in FIG. 1illustrates the configuration of aperture 34 prior to the sizing andcoining operation. The coining element 44 is provided with an angled diesegment 50 which annularly surrounds the opening 52 formed in element44. In a conventional coining operation, the die element 44 is impactedagainst the wall 52 of the G2 electrode 20 whereby the angled diesegment 50 of die element 44 induces the material of wall 52 to flowradially inwardly and to tightly conform to the diameter of sizing pin46. Thus, the aperture 34 is precisely sized to the diameter of thealignment mandrel 32 prior to the aligning operation utilizing device 10of FIG. 2.

Returning to FIG. 2, it will be understood that the tip 54 of themandrel 32 is provided with visible markings 56 which may be circulargrinding marks formed at the tip end which provide concentric indiciaabout the exact center 58 of the mandrel tip 54. If desired, othermarking indicia may be utilized to visibly define the exact center ofthe mandrel tip.

An operators microscope 60 which is used to magnify and view the tip 54of the mandrel 32 is positioned to view the openings of apertures 34 and36 and the visible segment of the tip 54. The mandrel 32 is providedwith a rotating knob 62 which may be turned by the operator to inducerotation of the mandrel 32 and its tip 54. The

operator, concurrently with rotation of the knob 62, views the apertures34 and 36 via the microscope 60 and if the apertures 34 and 36 aremisaligned the field of view appears as shown in FIG. 3. As shown inFIG. 3, it is obvious that the center of the opening 34 in the G2electrode 20 is misaligned with the opening 36 of the G1 electrode 18.To correct misalignment, three adjusting screws arranged in 120 degreeangular spacing (FIG. 5) may be alternately and selectively rotated toselectively apply distorting pressure to the respective adjusting screws24. The distortions induced by the adjusting screws 20 change theposition of the central aperture 34 of the G2 electrode 20 in relationto the central longitudinal axis of the carrying cylinder 16. Thischange results from small or minor distortions in the surface of thecylinder 16, as well as repositioning of the G2 electrode 20 internallyin the cylinder. The operation is successively repeated by the operatorwith continued visual examination of the appearance of the mandrel tip54 via the microscope 60 with concurrent rotation of the knob 62 untilsuch time as the center of the tip appears to be centrally aligned withthe aperture 36 of the G1 electrode 18'. The appearance upon a properalignment of the tip 54 is shown in FIG. 4. Once alignment is obtainedthe operator retracts adjusting screws 24 to relieve pressure inducedthereby, again checks the alignment of the openings 34 and 36 by mandrelrotation and if the center condition still obtains no further repetitivecentering operations are required.

If misalignment returns upon loosening of the adjusting screws 24, theabove described operations are repeated until exact aperture alignmentis obtained. After alignment has been properly obtained, adjustmentsleeve 22 may be removed, the electron gun supporting cylinder 16 can beremoved from mandrel 14 and thereafter subject to further fabrication.

As earlier noted, a major factor in the proper operation of an electrongun is the precise alignment of the beam passing apertures in the G1 andG2 electrodes. The present invention provides a mode for accuratelysizing the G2 aperture in a facile and economic manner. Additionally,the novel aligning jig provides an easy and simple mode of determiningboth the degree and direction of misalignment between the G1 and G2apertures of partially manufactured electron guns. In addition toproviding an easy check for possible misalignment, the device offers amode of simple and efiicient mechanical distortion of each gun to returnmisaligned apertures to proper alignment. Scrap loss during electron gunproductionis thereby minimized. V.

The invention as shown is by way of illustration and not limitation andmay be modified in many aspects, all within the scope and the spirit ofthe invention.

What is claimed is: V v 1 I 1. In a jig for aligning electrodeapertures'inan electron gun the combination of means to support acylindrical gun having electrodes therein secured to theQin'ne'r surfaceof the cylinder, aligning mandrel means positionable within an aperturein one of said electrodes and adjacent the aperture in anotherelectrode, said mandrel means having indicia on its tip to indicate thecenter thereof, means to rotate the mandrel to thereby visi-bly indicatethe relative position between the center of said other aperture and thecenter of the mandrel, and means to mechanically distort the cylinder toaccurately align said other aperture with the center of said mandreltip.

2. In a jig for aligning electrode apertures in an electron gunaccording to claim 1, and including an outer sleeve telescopicallyreceiving the cylinder, said outer sleeve having manually movable meansthereon to distort the wall of the outer cylinder.

3. In a jig for aligning electrode apertures in an elec- ReferencesCited UNITED STATES PATENTS 3,15 1,3 81 3,289,268 12/1966 Bernardis2925.19

CHARLIE T. MOON, Primary Examiner R. B. LAZARUS, Assistant Examiner U.S.Cl. X.R. 29467, 468

10/1964 Hedel 29 25.19

